Campaign 139

Campaign 139 (14 September 1969–25 April 1970) was a major military offensive of the People's Army of Vietnam, launched against its Royalist enemies during the Laotian Civil War. Larger than previous invading forces, Campaign 139 was also a combined arms expedition containing tanks, artillery, engineers, and Dac Cong sappers. As such, it was a decided escalation in the war. It was also an exceptional rainy season offensive by PAVN, which usually withdrew during the wet season.

Launched on 14 September 1969 with 60 tanks, 26 PAVN and 10 Pathet Lao battalions, plus supporting units, Campaign 139 drove from the Lao/DRV border into the strategic Plain of Jars in Military Region 2 of the Kingdom of Laos. The 16,000 plus invaders were opposed by a force of Central Intelligence Agency (CIA) sponsored hill tribes guerrillas some 5,500 to 6,000 strong. Hmong general Vang Pao's L'Armee Clandestine had just overrun the Plain during Kou Kiet, and the general elected to hold on. However, despite the best efforts of the guerrillas in a series of defensive clashes on and around the Plain, backed by massive air power, on 11 February 1970 the communists forced entrance to the Plain by capturing the crucial intersection of Routes 7/74. Having forced their way onto the Plain, the communists pushed their way across it to besiege the crucial main guerrilla base at Long Tieng. They overran the nearby refugee center at Sam Thong on 18 March 1970, and temporarily occupied the high ground overlooking the Lima Site 20A airstrip at Long Tieng used for resupplying the guerrillas. United States support of the irregulars was escalated, with the first B-52 Stratofortress Arc Light in northern Laos on 17 February, and the first ever use of the BLU-82 super-bomb on 22 March. On 18 March, irregular reinforcements were flown in from other military regions of Laos; so was a Royal Thai artillery battalion of mercenaries. Though the newly arrived guerrilla units were generally poor quality, they sufficed to fend off the exhausted PAVN. By 25 April 1970, the communists had fallen back onto their home ground near Dien Bien Phu, North Vietnam.

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